Tubular telescoping drive shafts are well known devices for transmitting rotational power between elements which may or may not be perfectly aligned about a rotational axis, and which may, from time to time, be varying distances apart. Such drive shafts often include one or more universal joints, such as a well known Hooke's joint. Reference in this regard, Suzuki et al. U.S. Pat. No. 6,692,365 issued Feb. 17, 2004.
A problem encountered with such known telescoping drive shafts is a lack of a disclosed capability to provide satisfactory function in a substantially fully retracted configuration wherein an inner drive shaft section including a universal joint is completely contained in an outer section and where misalignment is present, and which is also extendable telescopically to a much longer extended configuration.
As an example, modern cotton harvesters typically include a plurality of individual cotton picker row units supported in front of the harvester on a tool bar. Each of the individual row units requires connection to a rotatable power source, such as a transmission connected to an engine of the harvester, a fluid motor, electric motor, or the like. Such individual row units are typically relatively wide, but it is often desired to place adjacent ones of the units relatively close together, for instance, spaced apart on center lines 30 inches or so apart.
However, such row units from time to time require servicing and inspection, which necessitates separating adjacent ones of the units sufficiently to allow an operator to access side panels thereof between the adjacent units, which can entail increasing the spacing between the units, for instance, so as to have as much as about 44 inches between the center lines thereof. As a result, it is required to extend a drive shaft having an initial or retracted length of about 30 inches, to about 44 inches in length, which is about a 50% increase. With past telescoping drive shaft constructions used in this application, this has entailed disassembling components of the drive shaft connected to one of the adjacent row units from components of the shaft connected to the other of the adjacent row units. A resultant problem of this is that the driven row unit is no longer rotatably powered, and if rotation thereof is required for service, the unit must be manually driven, or the drive shaft reconnected which entails bringing the row units closer together, which can decrease access thereto and make servicing more difficult and time consuming. Additionally, an additional person or an alignment tool or support may be required for holding the disassembled components of the drive shaft in alignment for reassembly by the moving together of the adjacent row units.
Thus, what is sought is a tubular telescoping drive shaft which provides the capabilities set forth above and overcomes one or more of the shortcomings and problems of the prior art devices.